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The delicate art of catching fog in the desert

How do you turn mist into usable water? See how scarcity inspires ingenuity in parched Lima, Peru.

In the desert city of Lima, a city of 10 million people by the Pacific Ocean, mist is an important source of water. Water can be hard to come by on land, but thick blankets of fog roll in from the Pacific Ocean during the Southern Hemisphere city’s fall and winter months.

BySarah Gibbens

Photographs byAlessandro Cinque

March 21, 2023

8 min read

During the gray, cloudy months of fall and winter, more than 100 green nets can be found on the outskirts of Lima, Peru, harvesting a surprising resource—fog.

The technique is elegant in its simplicity. As water vapor catches in vertical nets, it condenses into liquid water and drips into a holding tank. Consisting of just two poles and a nylon net, the contraption can be a significant source of water, collecting between 50 to 100 gallons daily.

For some, it’s the only way to collect this vital resource.

fog obstructs the view of a mountainous area — *Garúa*, Spanish for “drizzle,” is the name Peruvians give to Lima’s seasonal fog. During this time of year, ocean currents push cool water from the deep ocean to the surface where it cools the air and forms thick, low-hanging clouds. The *garúa* continues traveling over land, through river valleys, until it hits the Andes Mountains.

abel cruz sits on a ledge with a fog net behind him — Abel Cruz knows what it’s like to live without water. After leaving his hometown of Cusco, Peru, he lived in one of Lima’s migrant camps where water is delivered by trucks for a hefty price. Now the industrial engineer is president of the non-profit which helps other communities create their own fog catchers.

Lima, shrouded in coastal mist for half the year, is the second largest city ever built in a desert. And migrants living on the city’s outskirts lack access to the plumbing that delivers safe drinking water to the rest of the city.

In camps like these, trucks deliver potable water at a markup sometimes a thousand times more expensive than the cost of tap water in affluent parts of Lima. The water collected from fog nets isn’t potable, but it can be used for bathing or boiled for cooking, cutting down on how much water needs to be purchased.

It was a disparity that industrial engineer Abel Cruz noticed 20 years ago when he moved to a migrant settlement where water was scarce. Cruz began thinking about how to turn Lima’s misty air into usable water and now, as the president of the organization Movimiento Peruanos Sin Agua, he shares his homegrown strategy with others in need.

For photographer Alessandro Cinque, projects like these illustrate the kind of ingenuity water-scarce communities will need more of in the future.

people unfolding the green fog nets — Residents of Lima’s Triunfo neighborhood prepare a fog-catching net. The invention is simple—a large nylon net is strung between two poles. As it traps fog, droplets condense like steam on a shower curtain and flow into water basins. Each net can last for five years.

a man stands on a ladder installing fog net — Fog nets can be enormous, more than 30 feet long and 30 feet tall, the size of two large cars stacked on top of each other. To fill their buckets, residents must climb a set of 20 stairs. For photographer Alessandro Cinque, the large nets, perched on hilltops, are reminiscent of Catholic crosses.

(See how Lima is using ancient technology to supply water during droughts.)

Fresh water is a dwindling resource. As climate change progresses, rainfall patterns are becoming less dependable. Cities from Cape Town, South Africa to Los Angeles are experiencing chronic drought. When rain does fall in these dry places, it’s more prone to deluge, a precipitation supercharged by a warmer atmosphere.

Today, about two-thirds of the world’s population experiences water scarcity for at least one month a year, according to the U.N., and by 2030, 700 million people might be forced to move to find water.

For Cinque, seeing the simple effectiveness of fog nets gave him hope that inexpensive tools can help people survive climate change.

“Seeing [the nets] from below reminded me of Catholic crosses on top of mountains,” he says. “I was surprised at how something so simple can really help people.”

fog nets above the village — Lima is in a coastal desert, and most of the city’s water is piped in from reserves of melted Andean glaciers and groundwater. But not everyone has access to city pipes. About 430,000 people live in Villa Maria del Triunfo, seen here, and about 20 percent experience extreme poverty.

a man walks through thick fog — Nicknamed *Lima la Gris* (Lima the gray), the city is overcast and dense with fog for half the year. Nets are used only during Lima’s fall and winter season, April through September, when coastal fog is thick enough for nets to collect water.

a man holding up a fog net above his head — Lima’s population has doubled in the past four decades. People move for jobs, education, healthcare, and some are forced from their homes as a result of climate change. Natural disasters, drought, shrinking glaciers, and other climate-related changes are imperiling the livelihoods of over 12 million Peruvians, according to a 2021 study.

a woman waters plants with converted fog net water — Using water she collected from fog nets, Mercedes Huamani Mitma grows a garden of fruits and vegetables that help feed her family. "Where there is water, there is life," she told Cinque.

a man fills barrels of water with a water supply truck — During the COVID-19 pandemic, the Peruvian government paid for local water supply companies to donate water to neighborhoods that previously had to pay for water delivered via trucks. Beginning March 2023, water will no longer be free, and water will often be marked up much higher than what inner city residents pay for their tap.

a truck navigates narrow rural roads — Technologies being developed to supply water in a changing climate can be expensive—like turning saltwater fresh. For those without resources or access, fog nets are simple: they work instantly, they last for years, and they help guarantee access to a basic human need.

Based in Peru, Alessandro Cinque photographs the environmental consequences of climate change, especially in Indigenous populations.

A new World Water Map allows people to find out about the water supply where they live. Typing in an address will reveal that area’s water gap—the difference between human demand for water and the renewable supply from sources such as rivers, lakes, and aquifers. The map—which was developed by National Geographic Explorer Marc Bierkens and Niko Wanders, with the support of the National Geographic Society, Utrecht University, and ESRI—also shows the regions where the water gap is highest and groundwater depletion most dire, including California’s Central Valley, Egypt’s Nile River Delta, and Pakistan’s Indus River Basin.

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